How to choose the right solar wire size?

Are you new to solar wiring? Or considering solar wiring similar to home wiring? Choosing wrong wires in solar installation could lead to excessive heat and fire.

Everyone is interested in solar technology, and most of us opt for it.

Installation of solar system is even easier and doesn’t require too much knowledge when you are dealing under 200-300 watts of solar installation. But when you are on a large capacity like one kilowatt or more you need to choose the right solar wire size.

In our home we use insulated copper wires and that can be used for small solar setups, but those copper wires are not suitable for outdoor wiring.

In solar setups most of the wiring is available outside the house, that’s why we need some special cables that can handle all the climatic conditions without disturbing the output of the solar wiring. So for the solar system we use heavily insulated tinned copper wire, and we do not use tape on joints instead we use MC4 connectors.

Know that solar wires are also known as DC wire, PV wire, and outdoor wire.

What are the difference between common house wire and solar wire?

The major difference between house wire and solar wire is the kind of wire and insulation material used. Normal house wires are made of copper which insulated with soft materials that can handle electricity heat; while solar wires are insulated with hard and some special materials that enables it to handle extreme level of heat and harsh weather conditions.

Yet another visible difference is their life. The house wire lasts 5 ~ 10 years that is based on the quality available in the market, while solar wire has a minimum of 25 years of life.

Choosing the right solar wire size.

Before we come to sizing, let’s calculate the Ampere you are going to generate from solar panels. Let’s consider you are planning to install 3 solar panels of 150 watts each, and the sum will be 450 watts. Each solar panel of 150 watts will generate around 8 Amps, so you’ll get about 24 Amps of current at its maximum output. So you’ll need to install either 4 mm2 or 6 mm2 of DC wire. For this setup even vendors say 4 mm2 enough but for better output and longevity with small room of upscale I’ll recommend 6 mm2.

Refer the below wire size table for more:

Current (in Amps)Gauge (American wire gauge)Size (in sq. mm)
15 A14 AWG2.5 mm2
20 A12 AWG4 mm2
30 A10 AWG6 mm2
40 A8 AWG10 mm2
55 A6 AWG16 mm2
Refer for further conversions.

Keep in mind that you never cheap out in wiring, specially in the sizing. Always maintain a room for a small upgrades, so you don’t need to change your wires.

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